<title>混合牛奶</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstdio&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;algorithm&gt;</span><span class="pl-cp"></span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>
<span class="pl-k">struct</span> <span class="pl-n">F</span><span class="pl-p">{</span>
        <span class="pl-kt">int</span> <span class="pl-n">p</span><span class="pl-p">,</span><span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">sp</span><span class="pl-p">;</span>
<span class="pl-p">};</span>
<span class="pl-kt">bool</span> <span class="pl-nf">cmp</span><span class="pl-p">(</span><span class="pl-n">F</span> <span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">F</span> <span class="pl-n">b</span><span class="pl-p">){</span>
        <span class="pl-k">return</span> <span class="pl-n">a</span><span class="pl-p">.</span><span class="pl-n">p</span><span class="pl-o">&lt;</span><span class="pl-n">b</span><span class="pl-p">.</span><span class="pl-n">p</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">(){</span>
        <span class="pl-n">freopen</span><span class="pl-p">(</span><span class="pl-s">&quot;milk.in&quot;</span><span class="pl-p">,</span><span class="pl-s">&quot;r&quot;</span><span class="pl-p">,</span><span class="pl-n">stdin</span><span class="pl-p">);</span>
        <span class="pl-n">freopen</span><span class="pl-p">(</span><span class="pl-s">&quot;milk.out&quot;</span><span class="pl-p">,</span><span class="pl-s">&quot;w&quot;</span><span class="pl-p">,</span><span class="pl-n">stdout</span><span class="pl-p">);</span>
        <span class="pl-kt">int</span> <span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-n">m</span><span class="pl-p">;</span>
        <span class="pl-n">F</span> <span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-mi">5005</span><span class="pl-p">];</span>
        <span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">m</span><span class="pl-p">);</span>
        <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;</span><span class="pl-n">m</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">){</span>
                <span class="pl-kt">int</span> <span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-p">;</span>
                <span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">p</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">a</span><span class="pl-p">);</span>
                <span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">sp</span><span class="pl-o">=</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">p</span><span class="pl-o">*</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">a</span><span class="pl-p">;</span>
        <span class="pl-p">}</span>
        <span class="pl-n">sort</span><span class="pl-p">(</span><span class="pl-n">f</span><span class="pl-p">,</span><span class="pl-n">f</span><span class="pl-o">+</span><span class="pl-n">m</span><span class="pl-p">,</span><span class="pl-n">cmp</span><span class="pl-p">);</span>
        <span class="pl-cm">/*</span>
<span class="pl-cm">        for(int i=0;i&lt;m;i++){</span>
<span class="pl-cm">                printf(&quot;%d %d\n&quot;,f[i].p,f[i].a);</span>
<span class="pl-cm">        }</span>
<span class="pl-cm">        */</span>
        <span class="pl-kt">long</span> <span class="pl-kt">long</span> <span class="pl-n">s</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">,</span><span class="pl-n">ssp</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span>
        <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;</span><span class="pl-n">m</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">){</span>
                <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">s</span><span class="pl-o">+</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">a</span><span class="pl-o">&gt;=</span><span class="pl-n">n</span><span class="pl-p">){</span>
                        <span class="pl-n">ssp</span><span class="pl-o">+=</span><span class="pl-p">(</span><span class="pl-n">n</span><span class="pl-o">-</span><span class="pl-n">s</span><span class="pl-p">)</span><span class="pl-o">*</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">p</span><span class="pl-p">;</span>
                        <span class="pl-k">break</span><span class="pl-p">;</span>
                <span class="pl-p">}</span>
                <span class="pl-k">else</span><span class="pl-p">{</span>
                        <span class="pl-n">s</span><span class="pl-o">+=</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">a</span><span class="pl-p">;</span>
                        <span class="pl-n">ssp</span><span class="pl-o">+=</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">sp</span><span class="pl-p">;</span>
                <span class="pl-p">}</span>
        <span class="pl-p">}</span>
        <span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;%lld&quot;</span><span class="pl-p">,</span><span class="pl-n">ssp</span><span class="pl-p">);</span>
        
<span class="pl-p">}</span>
</cpde></pre></div>